Study of erythrocyte delta-aminolevulinic acid dehydratase activity in porphyria cutanea tarda.

The erythrocyte delta-aminolevulinic acid dehydratase activity was studied in porphyria cutanea tarda patients, compared to healthy controls, in an attempt to resolve the contradictions in the relevant literature data. In an in vitro experimental system, a study was also made of how the erythrocyte delta-aminolevulinic acid dehydratase activity varies on the action of the activators -SH and Zn2+. It was found that, compared to the healthy controls, the erythrocyte delta-aminolevulinic acid dehydratase activity of porphyria cutanea tarda patients is significantly decreased, but it is restored to the original activity level on the addition of -SH and Zn2+. Since there is a general -SH requirement of delta-aminolevulinic acid dehydratase, the most obvious explanation for the decrease of the activity in the case of the patients is the shift of the natural redox systems of the erythrocytes, and the decrease of the reduced glutathione/oxidized glutathione ratio.